It has been a requirement in the technical field of hard disk drive devices to increase the data capacity, the read/write speed and the recording density. A key for realizing high data capacity is to keep a low flying height of a head/slider assembly above a recording disk. It is a requirement to precisely control static attitude of the head/slider assembly above the recording disk to realize the low flying height of the head/slider assembly. The static attitude refers to the attitude of the head/slider assembly attached to the flexure.
A magneto resistance (MR) head with four connecting wires has been used as a read/write head of the hard disk drive device. The stiffness of the four connecting wires affects the static attitude of the head/slider assembly.
FIGS. 1 and 2 show a prior art support arm which uses a relatively large head/slider assembly called as 50% type slider or nano type slider, which has dimensions of 1.6 mm (width).times.2.0 mm (length). The prior support arm contains an actuator arm 4 which has a pivot point 10 mounted on a frame of the hard disk drive device, a load beam 2, a mount plate 3 connecting the load beam 2 with the actuator arm 4, a flexure 7 attached to the load beam 2 at coupling points 8, and a head/slider assembly 1 mounted on the flexure 7. The head/slider assembly 1, the flexure 7, the load beam 2 and the mount plate 3 are referred to collectively as a head gimbal assembly (HGA).
A flexible tube 6 containing the four connecting wires 5 connected to the MR head 12 is mounted on one side edge of the support arm. It is noted that the tube 6 is fixed to the side edge at plural positions by fixing elements 14. A front end of the tube 6 is located near to the head/slider assembly 1, and the four connecting wires 5 extending from the front end are connected to the MR head 12, as shown in the FIGS. 1 and 2.
A dimple or extruded portion 13 attached to the load beam 2 engages with the flexure 7 supporting the head/slider assembly 1 to realize a gimbal type movement of the head/slider assembly 1. The prior art head support arm has the following two problems. The first problem is that the tube 6 containing the four connecting wires 5 is mounted at one of side edges and is positioned across the bending portion 11, so that the total stiffness of the tube 6 and the four connecting wires 5 applies a force to one of the side edges, i.e. an upper edge, and this force prevents the bending action of the upper side edge, whereby the bending action of the upper side edge mounted with the tube 6 and the four connecting wires 5 differ from the bending action of the lower side edge, thereby the load beam 2 tends to twist when the support arm is bent. This twist affects the static attitude of the head/slider assembly.
The second problem is caused by different stiffness of the four wires 5 connected to the MR head 12. If the bias force applied by each of the four connecting wires 5 to the MR head 12 is equal to each other, the head/slider assembly 1 can perform an ideal gimbal type movement in a rolling direction and a pitching direction on the dimple 13. The four connecting wires 5, however, extend from the front end of the tube 6 fixed on the upper side of the load beam 2, and hence the length of each of the four connecting wires 5 differ from each other and an angle of each of the four connecting wires 5 to the MR head 12 differ from each other, so that the stiffness of each of the four connecting wires 5 differ from each other, whereby the difference in the stiffness of each of the wires 5 remarkably affects the static attitude of the head/slider assembly 1 in the rolling direction.
For the reason described above, it is difficult to provide the ideal static attitude of the head/slider assembly 1, whereby it is difficult to precisely control the flying height of the 50% type head/slider assembly 1.
A recently developed head/slider assembly called as 30% type slider or pico type slider has smaller dimensions of 1.0 mm (width).times.1.25 mm (length).times.0.43 (height). The above described wiring scheme can not be used in the 30% type head/slider assembly, since the smaller head/slider assembly is more sensitive to the stiffness of the wiring system.